(1) Field of the Invention
The invention is related to a grid type fiber composite structure, particularly to a transverse force resilient grid type fiber composite structure for local load introduction, and a method of manufacturing such grid type structures.
(2) Description of Related Art
The document U.S. Pat. No. 3,391,511 describes a lightweight structure having a honeycomb interior. The structure includes cell units having outer and inner components, wherein the interiors of the cell units may contain air, or other gas, or may be filled with lightweight material, e.g. polyvinyl chloride foam. The perimeter of each outer component is formed by a wall having faces that comprise corrugations with flat crests extending from end to end of a corresponding cell unit. One end of each outer component is open and encircled by an intermittent flange and the other end is closed by an end wall which is integral with the wall. Into the open end of each outer component, an inverted inner component is inserted, which is generally similar to the corresponding outer component, but with a perimeter wall which is plain and sufficiently smaller to fit inside the outer component. The perimeter wall is bonded to the wall of the outer component by epoxy resin. The cell units are coated with epoxy resin and assembled in close relationship, i.e. with their corrugation crests abutting respective corrugation crests of neighboring cells, on a first sheet of felted glass fibers that is also soaked in epoxy resin and laid on a top surface of a support. A second sheet of felted glass fiber soaked in epoxy resin is laid upon the assembly. The epoxy resin forms bonds between the different components of the lightweight structure.
The document US2004140049 A1 discloses a method of manufacturing a hollow section grid-stiffened panel comprising a tool having a surface. The stiffened skin composite panel is preassembled comprising laminating a composite outer skin on the surface, placing a separator outer layer on the composite outer skin, and laminating a composite stiffener on the mandrel, the mandrel being positioned on the separator layer, wherein the separator layer separates the stiffener and the mandrel from the outer composite skin. The preassembled outer skin composite panel is cured on the tool. The separator layer and mandrel are removed from the preassembled stiffened skin composite panel. The stiffened skin composite panel is reassembled, comprising applying an adhesive between the composite outer skin and the composite stiffener. The reassembled stiffener skin composite panel is cured on the tool to bond the stiffener skin to the outer skin.
The document US2009038744 A1 discloses a cellular composite structure with a grid having groups of angularly intersecting ribs. The ribs of each group are oriented substantially in the same direction to each other and angularly oriented from the other rib groups. An additional rib defines a composite structure outer perimeter wall and can be differently angularly oriented from the other ribs. A contiguous rib wall is created by segments of ribs defined by rib intersections. The contiguous rib wall bounds a cavity. A multilayer sheet cap member with extending walls to engage the contiguous rib wall is positioned within the cavity. The engagement walls extend from individual sheet perimeter portions angularly oriented to the sheet. The ribs and cap member have pre-impregnated resin. Heating the cap member and ribs activates the resin and co-cures the composite structure.
The document EP 0 948 085 A2 relates to high stiffness parabolic structures utilizing integral reinforced grids and more particularly to a high stiffness parabolic structure utilizing an integral reinforcing grid which includes a skin sheet having a generally parabolic shape; and a grid attached to the skin sheet and having a triangular isogrid pattern.
The document DE 10 2009 053 053 A1 discloses a component with a rib structure provided with ribs that run along polygon edges, and including laminar grid-like polygons that are arranged next to each other. Two plate-shaped fiber composite structures containing carbon fibers represent the rib structure, where one of the fiber composite structures is fastened at a flat side of the other fiber composite structure and formed based on a flat fiber composite structure by inserting sections into an interior of a polygon and transforming produced structure projections to form the rib structure.
The document U.S. Pat. No. 4,052,523 A discloses a lattice type structural panel utilizing the unidirectional character of filamentary epoxy impregnated composites to produce stiff lightweight structural panels for use in constructing large area panels for space satellites and the like.
The document U.S. Pat. No. 4,012,549 A discloses a grid structure of I-beam members arranged in an integral repeating pattern of substantially equilateral triangles integral with a skin sheet covering the structure. The beam webs are filled with advanced composite materials comprising high-strength fibers in a supporting matrix. Preferably, the fibers run parallel to the beam webs for a structure of improved stiffness with a high strength-to-weight ratio.